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