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