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