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