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