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