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