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