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