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