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