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