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