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