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