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