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