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)(15,21)(16,20)(17,22)(18,28)(19,23)(24,25)(26,27) involution — undirected(1,2)(3,4)(5,7,9,8)(6,10,12,11)(13,14)(15,24)(16,26)(17,22)(18,28)(19,23)(20,27)(21,25)(5,7,9,8)(6,11,12,10)(13,15)(14,20)(16,17)(18,27)(19,25)(21,28)(22,24)(23,26)(2,4)(13,16,19,27)(14,21,23,24)(15,17,25,18)(20,28,26,22)(5,8,9,7)(6,11,12,10)(13,17,19,18)(14,22,23,28)(15,16,25,27)(20,24,26,21)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.