Behold, I got bored so I drew this, im thinking on writing a book about it.
The triangle of beliefs
Perhaps you might wish to include "deism", "theism", "apatheism" "antitheism", "secular Humanism", "agnostic theism", "ignosticism" or a host of other names people have adopted to describe their theological positions.
The use of "religion" as one of three positions in some type of contrast also seems to disregard nondeist religions such as Budhism.
To me a religion is a belief of a higher being/s
Atheism is a disbelief of a higher being/s
Agnostic knowledges that he does not have all the answers.
They are not the absolute definition, it has more to do if you believe or don't in God or your not too sure, and there are hybrids of two or all three has you pointed out some, others could be put into one of 3 categories.