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