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