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