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)(13,14,17,20)(15,22,24,19)(16,26,18,21)(23,27,28,25)(6,9)(7,11)(13,15)(14,19)(16,25)(17,24)(18,27)(20,22)(21,23)(26,28) involution — undirected(2,4)(13,14)(15,23)(16,21)(17,20)(18,26)(19,27)(22,25)(24,28) involution — undirected(6,9)(10,12)(14,20)(19,22)(21,26)(23,28) involution — undirected(5,7,8,11)(6,10,9,12)(13,16)(14,21)(15,24)(17,18)(20,26)(23,28)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.