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