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