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