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