In addition to the comments my colleague has made, I would like to add a couple of rhetorical strategies and expound on one of the aforementioned strategies I noted when reading Camus's "The Myth of Sisyphus."
Allusion is at the forefront, of course, with the titular character. But there is another allusion latter in the essay when Camus likens Sisyphus's struggle, and by extension our own endless bouts with our requisite boulders as "boundless grief . . . too heavy to bear . . . our nights of Gethsemane." This allusion to Christ's final night before his crucifixion helps us to understand the great depth of the grief for which we cannot find cause. According to Christian belief, when Christ was in the Garden of Gathsemane, he was so filled with suffering that he sweat drops of blood as he pleaded with God to change his path, but to no avail. Likening our grief to Christ's is Camus's way of explaining its immensity. The purpose of the allusions is to give the audience a point of reference. Our understanding of Christ's suffering gives us a better understanding of Sisyphus, and by extension, ourselves.
A second strategy I noted was the use of descriptive loose sentences. (I suppose this could be considered a combination of imagery and loose sentence structure.) The image of Sisyphus struggling to roll his boulder upward is strengthened when Camus describes how "one sees the face screwed up, the cheek tight against the stone, the shoulder bracing the clay-covered mass, the foot wedging it, the fresh start with arms outstretched, the wholly human security of two earth-clotted hands." The short, two-word main clause "one sees" followed by the loose string of descriptors provides a clear image of Sisyphus, and in addition, the list of body parts each completely consumed with struggle builds our understanding of the completeness of Sisyphus's punishment.
I further noted the occasional use of rhetorical questions . For example, when Camus asks, "Where would his torture be, indeed, if at every step the hope of succeeding upheld him?" and then follows with a description of every workman who goes through the same, endless mundane tasks day after day, he is doing so to provoke thought. His audience will supply the answer, but the answer is already suggested: there is no torture if hope of success exists. It is that lack of hope that creates the torture. By the same token, common man's mundane, repetitive existence is torture. Did Camus say this outright? No. But he caused his audience to make the connection to themselves and their own fruitless existence with his line of rhetorical questioning. Often, the very purpose of these questions is to plant an idea in the collective mind of the audience, to move them to believe that the answers to the questions, which are strongly suggested, are born within themselves rather than directed by the questioner. These types of questions are a highly effective rhetorical strategy because...
they move the audience in the desired direction while making the audience feel as if the conclusions they reach are their own, and, therefore, they own them.
As you can see, Camus's masterful use of rhetorical strategies leaves his audience with little choice but to agree with him, that if Sisyphus's existence (and by extension our own) is to have meaning, he and we must choose to believe he is happy. In this sense, joy is a choice.