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