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