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