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