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