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