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