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