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