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