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