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