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