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