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