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