One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,7,5,3,8,6)(9,10,14,18,15,20,13,19)(11,21,23,16,25,32,24,33)(12,26,28,36,29,35,30,17)(22,38,39,34,40,31,27,37)(9,11,15,25)(10,16,20,33)(12,27,29,39)(13,24,14,23)(17,34,36,37)(18,32,19,21)(22,30,40,28)(26,31,35,38)(1,3)(2,5)(4,6)(7,8)(9,12,13,28,15,29,14,30)(10,17,18,35,20,36,19,26)(11,22,23,27,25,40,24,39)(16,31,21,37,33,38,32,34)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.