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