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