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