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