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