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