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