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