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