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