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