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