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