Mark on the map the features discussed in the text. Do this for all the maps. If the model is based on somebody else model, give the reference. A good model can explain both gravity and magnetic data simultaneously. Also, magnetic highs are more likely due to contrasts in magnetic susceptibility in the basement than from topography of basement.
Color maps are preferred because they are easier to read and interpret.
Also, you should supplement your report with jpg or pdf versions of your color maps.