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