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