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