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