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