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