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