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