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