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