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