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