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)(11,12)(13,21)(14,15)(16,23)(17,18)(19,22)(20,24)(25,26,31,29)(27,33,28,32)(30,37,38,34)(35,39,36,40)(3,7)(5,8)(9,11)(10,12)(13,19)(14,17)(15,18)(16,20)(21,22)(23,24)(26,29)(32,33)(34,37)(39,40) involution — undirected(1,2)(3,5)(4,6)(7,8)(10,15)(11,17)(16,21)(19,24)(25,27,31,28)(26,32,29,33)(30,35,38,36)(34,39,37,40)(9,12)(10,11)(13,22)(14,18)(15,17)(16,24)(19,21)(20,23)(25,28,31,27)(26,33,29,32)(30,35,38,36)(34,39,37,40)(1,3)(2,5)(4,7)(6,8)(9,10)(11,18)(12,17)(13,16)(14,15)(19,22)(20,24)(21,23)(25,29,31,26)(27,32,28,33)(30,37,38,34)(35,39,36,40)(1,2)(3,5)(4,6)(7,8)(9,13)(10,16)(11,19)(12,20)(14,23)(15,21)(17,24)(18,22)(25,30)(26,34)(27,35)(28,36)(29,37)(31,38)(32,39)(33,40) 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.