The sounds you create are such a precious feature of your identity.
I tell parents to encourage their child by saying, "I love to hear you play. I love your sound." Although your instrument and the type of strings you use will certainly affect your sound, each person playing with the same cello and strings will produce their own unique sound.
Cellists often talk about sound in a more clinical way by calling it tone. I think the word "tone" implies a more specific aspect of your sound. You alter your tone by adjusting the bow speed, placement and weight. Those 3 variables can change the timbre and volume of your sound.
The way you use or don't use vibrato also has a huge influence on your sound.
To develop your sound, you must continually improve your technique, your listening and your understanding of the science behind sound production .
Also, use your imagination to come up with verbal descriptions of the sounds you want, using adjectives to describe the type of tone you want. All artists play around with contrasting elements, bringing out certain ones to emphasize a particular emotion.