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