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