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