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