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