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