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