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