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