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