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