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