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