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