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