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