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