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