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