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