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