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