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)(13,14,19,21,18,22,16,26)(15,23,24,28,25,20,27,17)(5,7)(6,9)(8,12)(10,11)(13,15)(14,20)(16,27)(17,21)(18,25)(19,24)(22,23)(26,28) involution — undirected(1,2,3,4)(13,16,18,19)(14,21,22,26)(15,24,25,27)(17,20,28,23)(7,12)(9,11)(14,22)(15,25)(21,26)(24,27) involution — undirected(6,10)(9,11)(13,17,19,23,18,28,16,20)(14,15,21,24,22,25,26,27)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.