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