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