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