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)(11,12)(13,14)(15,16)(17,18)(19,23)(20,21)(22,24)(25,26,31,28)(27,34,29,32)(30,33,38,36)(35,40,37,39)(10,14)(11,16)(17,19)(18,22)(20,23)(21,24)(25,27,31,29)(26,32,28,34)(30,35,38,37)(33,39,36,40)(10,14)(12,15)(17,19)(18,23)(20,22)(21,24)(25,28,31,26)(27,32,29,34)(30,33,38,36)(35,40,37,39)(1,3,5,8)(2,6,4,7)(9,11,13,16)(10,15,14,12)(25,29,31,27)(26,32,28,34)(30,37,38,35)(33,39,36,40)(1,4,5,2)(3,7,8,6)(9,12,13,15)(10,16,14,11)(17,20,21,18)(19,23,24,22)(25,30)(26,33)(27,35)(28,36)(29,37)(31,38)(32,39)(34,40)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.