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