The following book is a nice summary of classic work in graph coloring:
* Graph Coloring Problems, by Tommy R. Jensen and Bjarne Toft, 1994 DOI:10.1002/9781118032497.
The following book focues more on coloring algorithms:
* A Guide to Graph Colouring: Algorithms and Applications, by R.M.R. Lewis, 2016 ISBN:978-3319257280.