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