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