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