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