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