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