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