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