I don't know about a map, but most of the junk that there is to see is right by the diving entrance. It is all linked by lines. If you go to any of the buoys and follow the line down you should find something, follow the underwater lines around and it should lead you to various things that have been placed there. There is also a boat very close to the dam itself, I am not sure what the current depth is.
You can also dive the cove side which is an interesting dive. You don't have the junk that there is on the dam side but there are some walls, etc... There are some nice grottos and swimthroughs off the point but if you do it I would highly recommend diving thirds because you do not want to have to surface into boat traffic. You should also carry a SMB or some other surface marking device that you can send up to keep from getting hit by a boat if you must surface in the middle of the lake. In order to get very far out you will need good air consumption and/or a a tank larger than an aluminum 80.
~Jess