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