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