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