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