Litmus paper - turning red, blue and even bleached
I can supply some details now, and hopefully this ought to qualify as an answer.

As I mentioned earlier litmus is a mixture of 10-12 dyes (CAS number: 1393-92-6).

The acid-base indicator properties of litmus are primarily due to 7-hydroxyphenoxazone chromophore (pictured below)


The answer you linked to discusses the acid-base indication mechanism in some detail, so I shall skip over that. 

Anyway, what this serves to establishing that it is indeed a extended $\pi$-conjugated system that we are dealing with in the chromophore. 

Now, $\ce{HOCl}$ would bring about halohydrination (basically an electrophilic addition) across the $\pi$ bonds, thus disrupting the conjugated system. 

Halohydrins are compounds that contain an $\ce{-OH}$ and $\ce{-X}$ groups on adjacent carbons. 

This image describes the general mechanistic scheme in a simpler case: 


Anyway, after said addition reaction has taken place in the chromophore, the $\pi$-conjugated system is disrupted, and thus, we see an absence of colour.