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