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