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