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