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