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