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