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