The word "toilet" generally denotes the fixture itself rather than the room. A "bathroom" is a room containing a bath, a "washroom" is a room for washing hands, and a "restroom" is a room to rest in when tired; none of which would necessarily contain a toilet.
Also question is, what do you call a bathroom in England?
Although I have heard the room in question being referred to euphemistically as "The bathroom", I believe this to be an Americanism. Unless the bath is actually in there, it's a toilet, or a "loo" in more polite society. Certainly though some people refer to it as a "Lavvy", which is just a reduction of lavatory.
Why is the toilet called the John?
Thomas Crapper was a plumber that is often mistakenly called 'John Crapper'. While Sir John Harrington is credited with the invention, it was Alexander Cummings that received the first patent for a flushing water closet (toilet not John).