No one refers to a person. Sort of like no body. None is like there is zero of something. More like an amount. Sometimes it can refer to people as well. There is no one at the party. Did you see anyone? - No, I saw no one. Who are you with right now? - No one. I'm by myself. Do you have any candy? - No, I have none. None of them are blue. None of the people here like snow.

"No one" usually refers to people. It is the same as nobody. On the other hand, "none" could refer to things.