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