1. We show Straight cables as BLUE and Crossed as RED. That is our convention. The cable color can be anything you choose or, more likely, the vendor decides.
2. To avoid the need for Crossed cables many vendors provide UPLINK ports on Hubs or Switches - these are specially designed to allow the use of a STRAIGHT cable when connecting back-to-back Hubs or Switches. Read the manufacturers documentation carefully.
Increasingly vendor hubs (can you still buy them) and switches will auto-detect the connection type and internally switch the connectors so that STRAIGHT cables can be used everywhere.