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