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