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