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