If you take it almost word for word, it does translate to "It happens to you to sleep." What the sentence would translate to, however, is more akin to: "You happen to sleep sometimes." or "You sometimes sleep." Note that the "you" used is the polite or plural form of you. The sentence could also be used as a question, with the right intonation, and a question mark in written form. "Ça vous arrive de dormir?" would be asking "Do you sometimes sleep?". It is not perfect sentence structure, but in everyday speech it would be quite common.

As a question, it would be the equivalent of 'Do you ever sleep?'

¿Duerme unas veces?

"ca vous arrive de dormir" means " it happens to you to sleep"