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