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