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)(12,17,19,15)(13,16,21,18)(20,23,24,22)(27,33)(28,36)(31,34)(32,37)(3,7)(5,8)(10,11)(12,19)(16,18)(20,24)(25,26)(27,34)(28,37)(29,30)(31,33)(32,36)(35,39)(38,40) involution — undirected(1,2)(3,5)(4,6)(7,8)(13,21)(16,18)(20,24)(22,23)(26,30)(31,34)(32,37)(39,40) involution — undirected(9,11,14,10)(12,15,19,17)(13,18,21,16)(20,22,24,23)(25,27)(26,31)(28,38)(29,33)(30,34)(32,40)(35,36)(37,39)(1,3)(2,5)(4,7)(6,8)(9,12,14,19)(10,15,11,17)(13,20,21,24)(16,22,18,23)(25,28)(26,32)(27,35)(29,36)(30,37)(31,39)(33,38)(34,40)(1,2)(3,5)(4,6)(7,8)(9,13,14,21)(10,16,11,18)(12,20,19,24)(15,22,17,23)(25,26)(27,31)(28,32)(29,30)(33,34)(35,39)(36,37)(38,40)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.