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