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