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