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)(15,23)(16,19)(17,27)(18,22)(20,26)(21,25)(24,28) involution — undirected(1,2)(3,4)(6,10)(11,12)(15,24)(16,26)(17,25)(19,20)(21,27)(23,28) involution — undirected(5,7,9,8)(6,11,10,12)(13,15,25,24,18,26,17,16)(14,19,27,20,22,28,21,23)(2,4)(13,16,17,26,18,24,25,15)(14,20,21,19,22,23,27,28)(5,8,9,7)(6,11,10,12)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.