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