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