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