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