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