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