How does Camus emphasize through setting that the universe is a random and absurd place?
The setting in the short story "The Guest" resonates symbolically. Daru's schoolhouse is isolated on the steep plateau, reflecting his personal isolation from both the Arabs and the French, a moral divide. He does not want to be involved with the political conflict. In particular, Camus uses the odd weather to reflect the absurdity of the universe.The snowstorm has isolated Daru from his students, the only connection to humanity that he has until the prisoner comes. The snow becomes symbolic of man's isolation in a random world.
The criticism in the second link below addresses this question in specific detail.