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