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