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