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