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