I really enjoyed this post about how to convey information in graphs. Taking a simple Excel and changing it so that it conveys information more clearly. 

To accelerate that understanding, upgrade your line graphs to be efficient and truthful. Some broadly applicable principles should guide you to the right neighborhood.

http://www.eugenewei.com/blog/2017/11/13/remove-the-legend

Read the whole article for more. Perhaps Microsoft can upgrade this graphic capability for charts in the future in Excel.