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