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