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