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