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