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