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