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