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