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