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