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