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