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