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