One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,5)(3,7,8,6)(9,10,17,30,19,31,14,21,16,22,13,20,15,12,28,38)(11,18,33,40,36,39,32,37,27,35,24,34,26,29,25,23)(2,5)(6,7)(9,11,13,24,19,36,28,25,16,27,17,33,15,26,14,32)(10,18,20,34,31,39,38,23,22,35,30,40,12,29,21,37)(9,12,16,31)(10,19,22,15)(11,23,27,37)(13,30,17,20)(14,21,28,38)(18,32,35,25)(24,39,33,29)(26,40,36,34)(1,3,4,8)(2,6,5,7)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.