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