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