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