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