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