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