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