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