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)(13,14,19,23,18,21,17,24)(15,25,27,20,26,28,16,22)(5,6)(7,11)(8,10)(9,12)(13,15)(14,20)(16,19)(17,27)(18,26)(21,22)(23,25)(24,28) involution — undirected(2,4)(5,7)(6,9)(8,12)(10,11)(14,21)(15,26)(16,27)(23,24) involution — undirected(7,12)(9,11)(13,16,19,15,18,27,17,26)(14,22,23,25,21,20,24,28)(6,10)(9,11)(13,17,18,19)(14,23,21,24)(15,16,26,27)(20,28,22,25)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.