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