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