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