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