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