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