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