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