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