One vertex per element, one color per generator, with an edge from x to x·s.
(2,5)(6,8)(11,17)(14,18)(19,23)(22,24)(25,26,31,34)(27,33,29,32)(28,37,39,30)(35,36,38,40)(3,7)(6,8)(9,10)(11,14)(12,20)(13,16)(15,21)(17,18)(19,24)(22,23)(25,27,31,29)(26,32,34,33)(28,38,39,35)(30,40,37,36)(1,2)(3,6)(4,5)(7,8)(9,10,13,16)(11,14,17,18)(12,15,21,20)(19,22,23,24)(25,28)(26,30)(27,35)(29,38)(31,39)(32,36)(33,40)(34,37)(9,10)(11,18)(12,15)(13,16)(14,17)(19,24)(20,21)(22,23)(25,29,31,27)(26,33,34,32)(28,38,39,35)(30,40,37,36)(1,3,4,7)(2,6,5,8)(9,11,13,17)(10,14,16,18)(12,19,21,23)(15,22,20,24)(25,30)(26,28)(27,36)(29,40)(31,37)(32,35)(33,38)(34,39)(1,2)(3,6)(4,5)(7,8)(9,12,13,21)(10,15,16,20)(11,19,17,23)(14,22,18,24)(25,26)(27,32)(28,30)(29,33)(31,34)(35,36)(37,39)(38,40)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.