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