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