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