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