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)(25,26,32,36)(27,35,31,30)(28,37,39,33)(29,38,40,34)(1,2)(3,6)(4,7)(5,8)(9,11,14,20)(10,15,18,19)(12,21,23,13)(16,17,22,24)(25,27,32,31)(26,30,36,35)(28,34,39,38)(29,37,40,33)(1,3)(2,5)(4,8)(6,7)(9,10,14,18)(11,19,20,15)(12,16,23,22)(13,17,21,24)(25,28,32,39)(26,33,36,37)(27,34,31,38)(29,35,40,30)(3,8)(5,6)(9,10)(11,15)(12,22)(13,17)(14,18)(16,23)(19,20)(21,24)(25,29,32,40)(26,34,36,38)(27,37,31,33)(28,30,39,35)(1,3)(2,6)(4,8)(5,7)(9,12,14,23)(10,16,18,22)(11,13,20,21)(15,24,19,17)(25,30)(26,27)(28,29)(31,36)(32,35)(33,34)(37,38)(39,40)(1,2)(3,5)(4,7)(6,8)(9,13)(10,17)(11,12)(14,21)(15,22)(16,19)(18,24)(20,23)(25,31,32,27)(26,35,36,30)(28,38,39,34)(29,33,40,37)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.