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