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