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