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)(11,14)(12,15)(13,16)(17,20)(18,21)(19,22)(23,24)(25,26)(27,28)(29,37)(30,34)(31,32)(33,39)(35,40)(36,38) involution — undirected(2,5)(6,7)(10,11)(15,17)(16,18)(22,23)(25,27,31,30)(26,28,32,34)(29,35,39,38)(33,36,37,40)(1,2)(3,6)(4,5)(7,8)(13,21)(16,18)(19,24)(22,23)(26,32)(27,30)(33,37)(35,38) involution — undirected(1,3)(2,6)(4,8)(5,7)(9,11,14,10)(12,17,20,15)(13,18,21,16)(19,23,24,22)(25,28,31,34)(26,27,32,30)(29,36,39,40)(33,35,37,38)(9,12,14,20)(10,15,11,17)(13,19,21,24)(16,22,18,23)(25,29,31,39)(26,33,32,37)(27,35,30,38)(28,36,34,40)(9,13)(10,16)(11,18)(12,19)(14,21)(15,22)(17,23)(20,24)(25,30,31,27)(26,34,32,28)(29,38,39,35)(33,40,37,36)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.