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