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