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