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