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