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