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