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