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