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