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