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