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