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