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