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