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