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