[quote=@Kyoka]
I have been thinking of just trying to distinguish between prose, dialogue, and thoughts of the character using italic, bold, and speech marks.  The way coloured dialogue looks is very aesthetic imo but I have never been very good at picking suitable colours that looks good hehe
[/quote]

Honestly experiment as you will, but I feel like there's no need too if you don't want too. Use of colours is just a thing very popular in these games. 

Most people tend to pick based on their character, green for Hulk, Purple Hawkeye, Red for Flash, stuff like that.

A lot of people also colour code their supporting cast, it's just to make it easier/nicer to read I think. Though anyone that has a different reason, feel free to correct me!

Always find it interesting.