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