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