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