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