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