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