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