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