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