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