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