Critias, the follower of Socrates and brutal tyrant of Athens, also reinterpreted the myth of Sisyphus in an anti-teleological manner over two millenia before Camus did. It seems this is where Camus got his inspiration from, especially taking into consideration his interest in Greek plays.

Surviving fragment from Critias' play:
> “There was a time when human life was disordered and brutish… Then a man invented the fear of gods, placing them in the sky to observe everything…”