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