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)(11,12)(13,18)(14,16)(15,17)(19,20)(21,23)(22,24)(25,26,30,31)(27,33,35,28)(29,32,37,38)(34,39,40,36)(1,3,5,8)(2,6,4,7)(9,11)(10,15)(12,16)(13,19)(14,17)(18,22)(20,23)(21,24)(25,27)(26,28)(29,34)(30,35)(31,33)(32,36)(37,40)(38,39)(10,16)(11,17)(13,21)(20,22)(26,31)(28,33)(32,38)(36,39) involution — undirected(9,11)(10,12)(13,19)(14,17)(15,16)(18,20)(21,24)(22,23)(25,28)(26,27)(29,36)(30,33)(31,35)(32,34)(37,39)(38,40) involution — undirected(9,12)(10,17)(11,16)(13,20)(14,15)(18,24)(19,23)(21,22)(25,27)(26,28)(29,34)(30,35)(31,33)(32,36)(37,40)(38,39) involution — undirected(1,4,5,2)(3,7,8,6)(9,13,14,21)(10,18,16,23)(11,19,17,24)(12,20,15,22)(25,29,30,37)(26,32,31,38)(27,34,35,40)(28,36,33,39)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.