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