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