The first site provides you examples of different concept maps. It is not specifically for the branches of science, but it would help you determineyour own. The website tells you all about concept maps, how they are used and how you can create your own for a classroom.
The second site provides you with all the branches of science including the categories that fall beneath them.
The third site listed provides you with more fields of science, or at least a different way of looking at it than the second link. All of this information can be pooled to create your own concept map.
The fourth site may or may not have what you are looking for. It is a simple search in Google Images for branches of science. It has provided a number of different images that you could use as a concept map. You will find that many of the images do indeed offer the branches of science first with simplistic branches and then more in depth images.
With all four links you should be able to come up with a concept map for thebranches of science. If it is not exactly what you wanted, you can create your own. It will help you learn the branches of science and be a good project.
There is plenty of data out there to help you in finding what you need. The four sites are just a small amount of the information and sites you can pullfrom. If you want a professional looking concept map you may have to seek a bookstore that has school supplies. They may be able to order one for you, but there is the price you will need to pay for it to consider.