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