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