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