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