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