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