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