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