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