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