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