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