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