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