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