In XenForo you can point the ToS etc to whatever url you want.
For example, on xenfans.com I point it to http://xenfans.com/threads/xenfans-com-rules-policies.1167/
You could consider pushing it to a thread, a separate html page, or whatever you're comfortable with.
I've done it so it gives me more control and a wysiwyg editor to constantly update it.
So I looked at this forum, but I am not sure how to (as the second reply said) point it to a forum or thread? Help! I really just want to edit our ToS but I think it would be best to like the second reply said.