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