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