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