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