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