Original: The microarchitecture of a machine is usually represented as (more or less detailed) diagrams that describe the interconnections of the various microarchitectual elements of the machine, which may be everything from single gates and registers, to complete ALUs and even larger elements.
Simplified: Microarchitectual elements may be everything from single logic gates, to registers, lookup tables, multiplexers, counters, etc, to complete ALUs, FPUs and even larger elements.