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