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