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)(13,14,19,20,18,23,17,22)(15,24,26,27,25,16,21,28)(5,6)(7,11)(8,10)(9,12)(14,20)(15,25)(16,27)(17,19)(22,23)(24,28) involution — undirected(2,4)(5,7,8,12)(6,9,10,11)(13,15)(14,16)(17,21)(18,25)(19,26)(20,28)(22,27)(23,24)(7,12)(9,11)(13,16,19,28,18,24,17,27)(14,21,20,15,23,26,22,25)(6,10)(9,11)(13,17,18,19)(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.