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