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