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