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