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