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