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