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