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