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