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