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