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