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