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