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