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