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