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