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