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