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