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