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