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