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