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