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