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