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