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