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