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