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