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