They are very different. It would be difficult to list each difference. Hazard Communication requirements are the same (both follow 1910.1200).

Generally 1910-general insustry is stricter than 1926-construction in every way. Example:
Fall Protection, 1910 requires fall protection at 4 foot. 1926 requires fall protection at 6 foot, 10 foot for scaffolding, and 15/30 foot for steel erection activities (you will have to read the standard for additional guidance on that). The reason that 1910 is stricter is because it covers safety requirements for a stagnant facility. Construction is a very fast paced environment that is constantly changing. It would be near impossible to require fall protection at 4 foot in construction, vs a manufacturing facility, you can take time to evaluate each step of the process to eliminate fall protection issues.

My advice - Detemine whether the work falls under general industry activities (maintenance/repair) or construction activities (creating something, installation, etc.). Look up the specific standard for that scope of work. If it is questionable what standard to follow, always use the stricter standard (will most likely be 1910). End of the day, the client can always require what safety rules that contractors follow, if they argue that they want to follow 1926 rules while working in your facility, you can always tell them to follow your requirements or find another job.

Which 1910 are you asking about and which 1926.
If it crane 1910.180 or 1926.1400 sub cc. If you narrow it down I can help you out