Gregor's work life has two possible connections to his transformation. First, Gregor is a traveling salesman, and to put in good work he has to adhere to a strict schedule, performing the same tasks over and over to get the proper results. Insects are often ruled by instinct and a need to perform specific tasks; as Gregor is forced by his boss to continually perform his tasks, his body has taken on a more appropriate form that can multitask with its multiple legs, travel faster without a train, and doesn't tire as easily.
Another possible connection lies in Gregor's relationship with his boss. Thinking about how he wishes to sleep in instead of getting up early, Gregor muses:
...it's a funny sort of business to be sitting up there at your desk, talking down at your subordinates from up there, especially when you have to go right up close because the boss is hard of hearing."
(Kafka, The Metamorphosis, gutenberg.org)
Gregor's boss is like an insect queen, remaining at the office and sending his workers out to perform their repetitive tasks. His boss is also like a human dealing with insects, high above and not caring (hearing) what the insects have to say. Gregor has barely more autonomy than a beetle, and so his transformation is an apt allegory for the self-worth he feels in life.