Most applications stick to 16 colors (8 dark colors and 8 bright colors) known as ANSI colors, because that's the common denominator supported by almost all terminals. The ANSI standard doesn't specify the exact shade, it just says “black”, “blue”, “red”, etc. The default blue shade is often a pure blue that is hard to read on a black background on an RGB monitor, but good terminal emulators let you configure the colors. Adding a little bit of red and green into the color is typically enough to make it readable but still distinct.
With xterm, PuTTY, and other compatible terminals, you can configure the colors from an application running inside the terminal by emitting the proper escape sequence. Try running this in the terminal before you start the application:
## Set the blue hue (color 4) to CornflowerBlue
If you run bash when you open the terminal, put this in your
.bashrc. If the ansible application opens a terminal on its own, make it print this escape sequence to the terminal.
Alternatively, many terminals let you configure the colors in their configuration, for example through X resources in Xterm. Check the documentation of your terminal emulator.