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)(27,35)(28,38)(29,34)(30,32)(31,37)(33,39)(36,40) involution — undirected(1,2)(3,6)(4,5)(7,8)(9,10,14,11)(12,15,20,17)(13,16,21,18)(19,22,24,23)(25,27,30,37)(26,31,32,35)(28,36,39,34)(29,33,40,38)(2,5)(6,8)(13,21)(16,18)(19,24)(22,23)(26,32)(29,40)(31,35)(33,38) involution — undirected(3,7)(6,8)(9,11,14,10)(12,15,20,17)(13,18,21,16)(19,22,24,23)(25,27)(26,31)(28,34)(29,33)(30,37)(32,35)(36,39)(38,40)(1,3,4,7)(2,6,5,8)(9,12,14,20)(10,15,11,17)(13,19,21,24)(16,22,18,23)(25,28)(26,33)(27,36)(29,35)(30,39)(31,40)(32,38)(34,37)(1,2)(3,6)(4,5)(7,8)(9,13,14,21)(10,16,11,18)(12,19,20,24)(15,22,17,23)(25,29,30,40)(26,34,32,36)(27,33,37,38)(28,35,39,31)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.