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)(27,34)(28,33)(29,39)(30,35)(31,36)(32,38)(37,40) involution — undirected(1,2)(3,4)(5,6)(7,8)(9,11,15,12)(10,13,16,17)(14,19,23,20)(18,21,22,24)(25,27)(26,32)(28,37)(29,35)(30,33)(31,38)(34,36)(39,40)(2,6)(3,7)(10,16)(13,17)(18,22)(21,24)(25,28,31,29)(26,33,36,39)(27,37,38,35)(30,34,40,32)(3,7)(4,8)(9,12,15,11)(10,17,16,13)(14,19,23,20)(18,21,22,24)(25,29,31,28)(26,33,36,39)(27,35,38,37)(30,34,40,32)(1,3)(2,4)(5,7)(6,8)(9,13,15,17)(10,12,16,11)(14,21,23,24)(18,20,22,19)(25,27)(26,34)(28,35)(29,37)(30,33)(31,38)(32,36)(39,40)(1,4)(2,3)(5,8)(6,7)(9,14)(10,18)(11,19)(12,20)(13,21)(15,23)(16,22)(17,24)(25,30)(26,35)(27,33)(28,34)(29,32)(31,40)(36,37)(38,39) 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.