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