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