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