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)(11,20,23,29)(12,17)(13,18)(14,28)(15,19)(16,21,31,24)(22,34,36,39)(25,32)(26,38)(27,33)(30,35,40,37)(1,3,4,7)(2,5,6,8)(9,11,13,24,15,23,14,21)(10,16,18,29,19,31,28,20)(12,22,25,37,27,36,26,35)(17,30,32,39,33,40,38,34)(11,21,23,24)(16,29,31,20)(22,35,36,37)(30,39,40,34)(2,6)(5,8)(9,12,13,25,15,27,14,26)(10,17,18,32,19,33,28,38)(11,22,24,37,23,36,21,35)(16,30,29,39,31,40,20,34)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.