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