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