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