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