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