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