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