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