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)(15,20)(16,18)(17,19)(23,27)(26,28)(1,2)(3,4)(5,7)(6,8)(9,12)(10,11)(13,15,17,16)(14,18,19,20)(2,4)(6,10)(8,11)(15,16)(18,20)(21,22,25,24)(23,26,27,28)(5,7)(6,8)(9,12)(10,11)(13,14)(15,20)(16,18)(17,19)(21,23)(22,26)(24,28)(25,27) involution — undirected(1,2)(3,4)(5,8)(6,7)(9,11)(10,12)(13,16,17,15)(14,18,19,20)(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.