Genesis mining is actually a website which is offering a cloud mining service, i don't know if you were confusing with those two .
anyway, I'll suggest you to not easily fall for any cloud mining services especially those who are offering such thing which is too good to be true it will still be your choice but you still have a chance find different opportunity rather than cloud mining .
True. Cloud mining is a kind of service which is provided by genesis, hashflare, HashNest, nicehash, minergate etc.
Whatever names I just took will offer you legit way of earning money with cloud mining contracts. BUT it is not for sure that they will pay after long term contract. Your return of investment with $40 would be more than a year.
With $40 investment you will get around 0.05 TH/s of hash rate on genesis or hashflare. With this hashrate your daily earnings would be in cents and monthly would be few dollars. This won't be your net profit as you have to pay for electricity costs and maintenance charges. So after deductions you will have couple of dollars in a month. That would take you around one and half year to return 40 dollars.
So as you see that's big risk for few dollars.
Now you decide how you feel about investing into it.