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