See if this is what you're looking to do:
1. Click on the round Office Button in the upper left.
2. Click on Word Options in the lower right-hand corner of the box that pops
up.
3. Click on "Popular" on the left.
4. Click on the dropdown box next to where it says "Color Scheme," and
choose another color.
5. Click OK to get out of the box.
Hope that helps!