In most cases the kinds of info-graphic websites, blogs and portals act like references guided for people surfing the net, looking for information about paths, routes, business ventures, commercial entities and internet world rendered to them in visual and graphics shapes and no wonder those entities are having high PR and possibly very great web ranks because they act the same way as Wikipedia is currently operating in the cyber atmosphere.
Apparently, managers of those portals sometimes are employees of very big organizations and educational offices governed by companies or even governments and if your website or profile contains some valuable information, about the same niches and issues already talked about by their sites and then you get in touch with them directly and ask for some links, they might consider the option as even such links may not be purchased often.
Just do link trade and initialize a thread about your requirements. You can either do link exchange or buy links depends on your budget. Some sites lik linkbuildersnetwork.com will really helpful to contact those who offers links in info graphics and I want you to please contact those and get links. I think there is no other way to get links from those sites.
When I queried about it, i found it is useful infographicsshowcase.com/other-infographics-sites. Also don't forget to query Google and there i have found a lot like that. All the best.