What's the right way to tell someone (a college friend) that you don't want to hang out with them?

no right way. Just stop seeing them, they will get the idea.

just dont,anytime they wana hang out say youre busy, anytime they text you keep it short or on read, they will just stop talking too u and thats it... its harsh but its actully better that way than saying " dont think we can talk anymore" lol just heartbreaking or they will see you as a A-hole.

Hmm for me Id just not take his calls or decline hanging out a few times and he probably will get idea.

" we've grown apart dear
sorry and good bye"