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)(13,14,18,19)(15,20,17,16)(21,22,25,26)(23,28,27,24)(6,7)(10,11)(13,15,18,17)(14,16,19,20)(21,23)(22,24)(25,27)(26,28)(2,3)(14,19)(16,20)(22,26)(23,27) involution — undirected(1,3,4,2)(5,7,9,6)(8,11,12,10)(13,16)(14,15)(17,19)(18,20)(21,22)(23,28)(24,27)(25,26)(5,8,9,12)(6,10,7,11)(13,17,18,15)(14,16,19,20)(21,24,25,28)(22,27,26,23)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.