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