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