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