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