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