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