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