Originally I already added a comment since your question was locked, but I'm happy to see it's open again now.
In short, the fast (but still legal and not detrimental to the actual work) way to diversify is to introduce positions that have more diverse pool of applicants. Entry level positions have big pools => bigger chances. Other types of positions, such as designer, HR have a more diverse pool (if by any chances you guys would benefit from that employee).
Other than that, people of different skin colours and sexes are looking for the same thing - fulfilling work for a fair pay. Provide that and you'll get the most possible candidates. It's not your fault the pools are what they are.
In the meanwhile, be nice to your current employees. I don't know how I would feel if I saw my boss writing "there's too many white female sexually ambiguous employees here, how do I change that". I know you mean well, but try to look from their perspective.
You can make your workplace ready for diverse hires by standing up for your current employees. In my experience, anyone who had strong feelings about how women should be also had strong feelings about how other men should be (and would let others know). Eg, I work in IT and one guy just nonchalantly joked about some guy asking if a meal contains milk. Because apparently lactose intolerance is hilariously unmanly.
But I hope this last part is irrelevant to you and guys in your company are respectful of each other. Even among straight white men there's enough diversity and making sure that's respected is good training wheels for a more diverse group. If they are respectful to each other, it's unlikely they'll suddenly be rude to a new hire.