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