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