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