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