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