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