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