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