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)(26,31)(32,40)(33,35)(34,39)(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)(27,35)(28,33)(29,31)(30,39)(32,36)(34,38)(37,40)(1,4,5,3)(2,6,7,8)(25,27,29,28)(26,32,31,40)(30,37,38,36)(33,39,35,34)(9,12,14,13)(10,16,17,21)(11,19,20,22)(15,23,18,24)(25,28,29,27)(26,33,31,35)(30,37,38,36)(32,39,40,34)(9,13,14,12)(10,16,17,21)(11,19,20,22)(15,24,18,23)(26,34)(30,38)(31,39)(32,33)(35,40)(36,37)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.