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