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)(13,14,18,16)(15,17,20,19)(21,22,24,26)(23,27,28,25)(5,7,9,8)(6,10,11,12)(13,15,18,20)(14,19,16,17)(23,28)(25,27)(6,11)(10,12)(15,20)(17,19)(21,22)(23,25)(24,26)(27,28) involution — undirected(1,2)(3,4)(5,8,9,7)(6,12,11,10)(13,16,18,14)(15,19,20,17)(21,23)(22,25)(24,28)(26,27)(5,6)(7,12)(8,10)(9,11)(13,17,18,19)(14,15,16,20)(21,22)(23,25)(24,26)(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.